JP2007237329A - Cutting throwaway tip made of surface coated cermet having hard coating layer exhibiting excellent chipping resistance in high-speed cutting of high hardened steel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coated cutting tip having a hard coating layer exhibiting excellent chipping resistance in the high-speed cutting of a high hardened steel. <P>SOLUTION: A (Ti, Zr)CN layer among the hard coating layers is composed of a modified (Ti, Zr)CN layer showing a constituent atomic shared lattice point distribution graph which has the highest peak in Σ3 and 60% or more of distribution ratio of Σ3 with respect to the whole by irradiating the electron beam to each of the crystal grains existing in the measuring range of the surface polishing surface using a field emission type scanning electronic microscope, by measuring the angles of inclination of a normal of (001) plane and (011) plane which are crystal planes of the crystal grain to the normal of the polishing surface in the constituent atomic shared lattice point distribution graph is created based on the angles of the inclination obtained as the result. The surface of the Al<SB>2</SB>O<SB>3</SB>layer is polished and has a surface roughness Ra of 0.2 μm or less, and the pattern for reducing the remaining stress of the hard coating layer is formed on the polishing surface by the laser beam irradiation. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention is a surface-coated cermet cutting throwaway tip that exhibits excellent chipping resistance, especially when used for high-speed cutting of hardened steel such as hardened materials of alloy tool steel and bearing steel ( Hereinafter, it is related to a coated cutting tip).

Conventionally, generally, for example, as illustrated in a schematic perspective view in FIG. 14, a tungsten carbide (hereinafter referred to as WC) -based cemented carbide or titanium carbonitride (hereinafter referred to as TiCN) -based cermet, and a central portion A cermet base (hereinafter referred to collectively as a chip base) having a tool mounting bolt through hole (in the case where the mounting is performed by clamping with a clamp piece, the bolt through hole does not exist). ) On the entire rake face and flank face including the cutting edge ridge
(1) As the first layer, a chemical vapor deposition formed titanium nitride (hereinafter referred to as TiN) layer or titanium carbonitride (hereinafter referred to as TiCN) layer, or a laminate of both layers, and A first adhesive bonding layer having an average layer thickness of 0.1 to 1 μm;
(2) The second layer is formed by chemical vapor deposition,
Composition formula: (Ti _1-A Zr _A ) C _1-B N _B (wherein A is 0.02 to 0.15 and B is 0.3 to 0.55 in atomic ratio),
A high-temperature strengthening layer comprising a composite carbonitride of Ti and Zr satisfying the following [hereinafter referred to as (Ti, Zr) CN] layer and having an average layer thickness of 2.5 to 15 μm;
(3) As the third layer, either a titanium carbonate (hereinafter referred to as TiCO) layer formed by chemical vapor deposition or a titanium carbonitride oxide (hereinafter referred to as TiCNO) layer, or a laminate of both layers is formed. And a second adhesive bonding layer having an average layer thickness of 0.1 to 1 μm,
(4) As the fourth layer, a high-temperature hard layer comprising an aluminum oxide (hereinafter referred to as Al ₂ O ₃ ) layer formed by chemical vapor deposition and having an average layer thickness of 1 to 15 μm,
A coated cutting tip formed by forming a hard coating layer composed of the above (1) to (4) is known, and this coated cutting tip is used for continuous cutting and intermittent cutting of various steels and cast irons, for example. It is also known that
Furthermore, the surface of the Al ₂ O ₃ layer (high-temperature hard layer) constituting the fourth hard coating layer of the coated cutting chip may be smoothed by wet blasting for the purpose of improving cutting performance. Are known.
JP 2001-11632 A

  In recent years, the performance of cutting machines has been remarkable. On the other hand, there is a strong demand for labor saving, energy saving, and cost reduction for cutting work, and along with this, cutting work tends to be further accelerated. In the coated cutting tip, when the work material is a high hardness steel such as a hardened material of alloy tool steel or bearing steel, the cutting speed is 130 m / min. In the case of before and after, chipping (small chipping) hardly occurs in the hard coating layer, but the cutting speed is 250 m / min. When cutting is performed at the above high speed, chipping (slight chipping) is likely to occur in the hard coating layer, and as a result, the service life is reached in a relatively short time.

In view of the above, the inventors of the present invention have a cutting speed of 250 m / min. (Ti, Zr) CN, which is a second high-temperature strengthening layer of the hard coating layer, in order to develop a coated cutting chip in which no chipping occurs in the hard coating layer even when cutting is performed at the above high speed. Layer, that is, heat resistance due to the inclusion of the Zr component and relatively high high-temperature strength due to the inclusion of the Ti component, and as shown schematically in FIG. 1 (a), Ti, Zr, carbon, and nitrogen at the lattice points Paying attention to the (Ti, Zr) CN layer having a crystal structure of NaCl type face centered cubic crystal (where FIG. 1 (b) shows a state cut by the (011) plane) in which each of the constituent atoms consisting of As a result of research,
(A-1) (Ti, Zr) CN layer (hereinafter referred to as conventional (Ti, Zr)) which is a second high-temperature strengthened layer (hereinafter referred to as conventional high-temperature strengthened layer) constituting the hard coating layer of the conventional coated cutting tip CN layer) is, for example, a normal chemical vapor deposition apparatus,
Reaction gas composition: by _{volume%, TiCl 4: 1~5%,} ZrCl 4: 0.1~1%, CH 3 CN: 0.6~5%, N 2: 25~45%, H 2: remainder,
Reaction atmosphere temperature: 750-980 ° C.
Reaction atmosphere pressure: 2.7 to 13.5 kPa,
It is formed by vapor deposition under the conditions (called normal conditions).
Reaction gas composition: by _{volume%, TiCl 4: 15~20%,} ZrCl 4: 0.5~3%, CH 3 CN: 5~10%, CH 4: 0.5~5%, N 2: 20~ 35%, H ₂ : remaining,
Reaction atmosphere temperature: 1000 to 1050 ° C.
Reaction atmosphere pressure: 6-20 kPa,
In other words, in the reaction gas composition, TiCl ₄ and CH ₃ CN are relatively high and CH ₄ gas is newly added to further increase the ambient temperature. When vapor deposition is performed under (reactive gas composition adjustment high temperature conditions), the (Ti, Zr) CN layer (hereinafter referred to as a modified (Ti, Zr) CN layer) formed under the resultant reaction gas composition adjustment high temperature conditions has a high temperature strength. Will further improve and contribute to the chipping resistance improvement of the hard coating layer.

(A-2) About the conventional (Ti, Zr) CN layer and the modified (Ti, Zr) CN layer of (a) that constitute the second layer of the hard coating layer of the coated cutting tip,
Using a field emission scanning electron microscope, as illustrated in the schematic explanatory diagrams in FIGS. 2A and 2B, each crystal grain existing within the measurement range of the surface polished surface is irradiated with an electron beam, The inclination angle formed by the normal lines of the (001) plane and the (011) plane, which are the crystal planes of the crystal grains, with respect to the normal line of the surface polished surface (FIG. 2A shows (001) of the crystal planes. When the tilt angle of the surface is 0 degree and the tilt angle of the (011) plane is 45 degrees, the tilt angle of the (001) plane is 45 degrees and the tilt angle of the (011) plane is 0 degree. In this case, the crystal grains are composed of Ti, Zr, carbon, and nitrogen at lattice points as described above. It has a NaCl-type face-centered cubic crystal structure in which each atom exists, and based on the measured tilt angle obtained as a result. A distribution of lattice points (constituent atom shared lattice points) in which each of the constituent atoms shares one constituent atom between the crystal grains at an interface between adjacent crystal grains is calculated, and the constituent atomic shared lattice points are calculated. A constitutive atom shared lattice point form in which there are N lattice points that do not share constituent atoms in between (N is an even number of 2 or more in the crystal structure of the NaCl type face centered cubic crystal) is represented by ΣN + 1, and each ΣN + 1 is represented by ΣN + 1 When a constituent atomic shared lattice point distribution graph showing the distribution ratio occupying the whole (however, the upper limit is set to 28 in relation to the frequency) is created, the highest peak exists in Σ3 in any (Ti, Zr) CN layer However, the conventional (Ti, Zr) CN layer, as illustrated in FIG. 4, shows a relatively low constituent atom shared lattice point distribution graph in which the distribution ratio of Σ3 is 30% or less. Quality (Ti, Zr) CN layer , As illustrated in FIG. 3, shows an extremely high atom sharing lattice point distribution graph of the distribution ratio is 60% or more of the [sum] 3, the distribution ratio of the high [sum] 3 is a TiCl ₄ and CH 3 _CN constituting the reaction gas , Change depending on CH ₄ content and atmospheric reaction temperature.

(B-1) The smoothness of the vapor deposition surface of the Al ₂ O ₃ layer constituting the fourth high-temperature hard layer of the hard coating layer in the above-mentioned coated cutting tip is not sufficiently satisfied, and In the wet blasting, as a spraying abrasive, a polishing liquid containing 15 to 60% by mass of aluminum oxide fine particles (hereinafter referred to as Al ₂ O ₃ fine particles) in a ratio to the total amount with water is sprayed, When polished, the Al ₂ O ₃ layer is measured based on the compliant standard JIS B0601-1994 (the following surface roughness is all measured based on the compliant standard), Ra: 0.3-0 The surface roughness of 6 μm is shown, but when the smoothed surface of the Al ₂ O ₃ layer as a result has a surface roughness of Ra: 0.3 to 0.6 μm, chipping resistance of the hard coating layer There should be no noticeable effect on improving the performance.

(B-2) On the other hand, as illustrated in the schematic perspective view of FIG. 12, on the entire rake face and flank face including the cutting edge ridge line portion of the Al ₂ O ₃ layer constituting the fourth layer of the hard coating layer,
(B-2-1) First, as a lower layer, the reaction gas composition is in volume%,
TiCl ₄ : 0.2 to 10%,
CO ₂ : 0.1 to 10%,
Ar: 5 to 60%,
H ₂ : Remaining
And
Reaction atmosphere temperature: 800-1100 ° C.
Reaction atmosphere pressure: 4 to 70 kPa (30 to 525 torr),
And having an average layer thickness of 0.1 to 3 μm and a ratio of oxygen to Ti of 1.25 to 1.90 as measured by an Auger spectrometer,
Composition formula: TiO _W ,
In the case of
W: 1.25 to 1.90 in atomic ratio,
Forming a titanium oxide layer that satisfies
(B-2-2) Next, on the titanium oxide layer (lower layer), as an upper layer, the normal conditions, that is, the reaction gas composition in volume%,
TiCl ₄ : 0.2 to 10%,
N ₂ : 4-60%,
H ₂ : Remaining
And
Reaction atmosphere temperature: 800-1100 ° C.
Reaction atmosphere pressure: 4 to 90 kPa (30 to 675 torr),
When a TiN layer having an average layer thickness of 0.05 to 2 μm is formed under the conditions described above,
(B-2-3) At the time of forming the TiN layer (upper layer), oxygen in the titanium oxide layer constituting the lower layer diffuses and the upper layer (TiN layer) is constituted by a titanium oxynitride layer. However, in this case, the titanium oxide layer, which is the lower layer after the formation of the upper layer (the titanium oxynitride layer), has a ratio of oxygen measured by an Auger spectrometer at the center in the thickness direction. 1.2-1.7 atomic ratio to Ti,
Composition formula: TiO _x ,
In the case of
X: 1.2 to 1.7 in atomic ratio,
Titanium oxide layer that satisfies
(B-2-4) In addition, the upper layer composed of the titanium oxynitride layer was also measured at the center in the thickness direction with an Auger spectroscopic analyzer, and the ratio of diffused oxygen was the atomic ratio with respect to nitrogen (N). 0.01-0.4, i.e.
Composition formula: TiN _1-Y (O) _Y ,
(Where (O) represents diffused oxygen from the lower abrasive layer),
Y: 0.01 to 0.4 in atomic ratio
Titanium nitride oxide layer that satisfies

(B-3) With the titanium nitride oxide layer (upper layer) and the titanium oxide layer (lower layer) deposited and formed,
When a polishing liquid containing 15 to 60% by mass of Al ₂ O ₃ fine particles as a spraying abrasive in a ratio to the total amount of water is sprayed by wet blasting as in (b-1) above, the nitrogen The titanium oxide layer and the titanium oxide layer were pulverized and atomized by the Al ₂ O ₃ fine particles, and became titanium nitride oxide fine particles and titanium oxide fine particles, which acted as an abrasive in the presence of the Al ₂ O ₃ fine particles. As illustrated in the schematic perspective view, the surface of the Al ₂ O ₃ layer constituting the fourth layer of the hard coating layer is polished, and as a result, the surface of the Al ₂ O ₃ layer after polishing is Ra: When the surface roughness of the Al ₂ O ₃ layer is smoothed to a surface roughness of Ra: 0.2 μm or less, the chipping resistance is remarkable. The improvement effect comes to appear.

(C-1) On the other hand, the hard coating layer is formed by being deposited on the surface of the chip substrate at a reaction temperature of about 1000 ° C. and cooled to room temperature by a chemical vapor deposition apparatus. In the process, since the thermal expansion coefficient of the hard coating layer is relatively larger than the thermal expansion coefficient of the chip substrate, tensile stress remains in the hard coating layer. Residual tensile stress in the layer acts to promote chipping in high-speed cutting.

(C-2) On the other hand, a single basic shape mark, for example, a single basic shape mark such as a circle, a triangle and a quadrangle, or a similar shape thereof, is used for either the rake face or the flank face of the coated cutting tip. As shown in a schematic perspective view of an embodiment in which the single basic shape mark is circular, for example, as shown in FIGS. Either or both of the shape mark and the collective mark of the single basic shape mark are distributed (in this case, the examples shown in FIGS. 5 to 7 have a relatively thin hard coating layer, 9 and FIGS. 10 and 11 show the distribution mode when the layer thickness increases, and any one of the constituent layers of the hard coating layer is exposed to the single basic shape mark. As a digging surface The conditions (in this case, the depth of the exposed surface of the single basic shape mark is individually adjusted according to the layer thickness of the hard coating layer, but in order to reduce the residual stress efficiently, the layer thickness When a laser beam irradiation pattern is formed at a depth corresponding to 5 to 20%), the residual stress of the hard coating layer is remarkably reduced. By the formation of the hard coating layer residual stress reduction pattern, In particular, the occurrence of chipping of the hard coating layer during high-speed cutting of high-hardness steel is significantly suppressed.

(D) The modified (Ti, Zr) CN layer constituting the second layer of the hard coating layer has the above-mentioned conventional (Ti, Zr) CN in addition to the high temperature strength and heat resistance of (Ti, Zr) CN itself. Zr) The surface of the Al ₂ O ₃ layer constituting the fourth layer of the hard coating layer is smoothed to a surface roughness of Ra: 0.2 μm or less, having a higher high-temperature strength than the CN layer. Since the chipping resistance of the hard coating layer is remarkably improved by forming the hard coating layer residual stress reduction pattern, the coated cutting tip formed by vapor-depositing the hard coating layer having such a configuration has a cutting speed of 250 m. / Min. Even when high-hardness steel is machined at high speeds as described above, chipping does not occur in the hard coating layer, and excellent wear resistance is exhibited over a long period of time.
The research results shown in (a) to (d) above were obtained.

The present invention has been made based on the above research results, and the entire rake face and flank face including the cutting edge ridge line portion of the chip base composed of the WC-based cemented carbide or TiCN-based cermet,
(1) As the first layer, a first adhesion formed by chemical vapor deposition, either a TiN layer or a TiCN layer, or a laminate of both layers, and having an average layer thickness of 0.1 to 1 μm. The bonding layer (2) is formed by chemical vapor deposition as the second layer,
Composition formula: (Ti _1-A Zr _A ) C _1-B N _B (wherein A is 0.02 to 0.15 and B is 0.3 to 0.55 in atomic ratio),
A high-temperature strengthening layer comprising a (Ti, Zr) CN layer satisfying the following conditions and having an average layer thickness of 2.5 to 15 μm:
(3) As a third layer, a second adhesion bonding layer comprising either a TiCO layer and a TiCNO layer formed by chemical vapor deposition, or a laminate of both layers, and having an average layer thickness of 0.1 to 1 μm,
(4) As the fourth layer, a high-temperature hard layer comprising an Al ₂ O ₃ layer formed by chemical vapor deposition and having an average layer thickness of 1 to 15 μm,
In the coated cutting tip formed by forming the hard coating layer composed of (1) to (4) above,
( _A ) _A high-temperature strengthening layer, which is the second layer of the hard coating layer, is also formed by chemical vapor deposition, and has a composition formula (Ti _1-A Zr _A ) C _1-B N _B (however, in terms of atomic ratio, A Is 0.02 to 0.15, B is 0.3 to 0.55), and further has an average layer thickness of 2.5 to 15 μm.
Using a field emission scanning electron microscope, each crystal grain existing within the measurement range of the surface polished surface is irradiated with an electron beam, and the crystal plane of the crystal grain is normal to the surface polished surface ( The inclination angle formed by the normal lines of the (001) plane and the (011) plane is measured. In this case, the crystal grains are NaCl-type face-centered cubes each having a constituent atom composed of Ti, Zr, carbon, and nitrogen at lattice points. A lattice in which each of the constituent atoms shares one constituent atom between the crystal grains at the interface between adjacent crystal grains based on the measured tilt angle obtained as a result of the crystal structure The distribution of the points (constituent atom shared lattice points) is calculated, and there are N lattice points that do not share the constituent atoms between the constituent atom shared lattice points (N is an even number of 2 or more in the crystal structure of the NaCl type face centered cubic crystal). ΣN is the existing configuration of atomic atom lattice points. In the constituent atom sharing lattice distribution graph showing the distribution ratio of each ΣN + 1 in the entire ΣN + 1 (however, the upper limit value is 28 due to the frequency), the highest peak exists in Σ3, A modified high-temperature strengthened layer comprising a modified (Ti, Zr) CN layer showing a constituent atom shared lattice point distribution graph in which the distribution ratio of Σ3 to the entire ΣN + 1 is 60% or more;
Consisting of
(B) On the entire surface of the Al ₂ O ₃ layer which is the fourth high-temperature hard layer of the hard coating layer,
(B-1) The lower layer has an average layer thickness of 0.1 to 3 μm, and
Composition formula: TiO _x ,
, Measure the central part in the thickness direction with an Auger spectrometer,
X: 1.2 to 1.7 in atomic ratio,
Satisfying titanium oxide layer,
(B-2) The upper layer has an average layer thickness of 0.05 to 2 μm, and
Composition formula: TiN _1-Y (O) _Y ,
(However, (O) indicates the diffused oxygen from the Ti oxide layer), the central portion in the thickness direction is also measured with an Auger spectrometer,
Y: 0.01 to 0.4 in atomic ratio
Satisfying titanium oxynitride layer,
In a state where the abrasive layer constituted by (b-1) and (b-2) is formed by vapor deposition,
(B-3) In wet blasting, a polishing liquid containing 15 to 60% by mass of Al ₂ O ₃ fine particles as a spraying abrasive in a proportion of the total amount with water is sprayed.
Al constituting the fourth layer of the hard coating layer in the presence of the ground titanium oxide particles in the lower layer, the ground titanium nitride oxide particles in the upper layer, and the Al ₂ O ₃ particles as the spray abrasive. _The rake face portion and the flank face portion including at least the cutting edge ridge line portion of the ₂ O ₃ layer are polished, and the surface roughness of these polished surfaces is set to Ra: 0.2 μm or less,
(C) Furthermore, either one or both of the rake face and the flank face of the polished surface, or the single basic shape mark and the collective mark of the single basic shape mark are distributed over the entire surface of both surfaces. A hard coating layer residual stress reduction pattern is formed by irradiating a laser beam with the single basic shape mark as a dug surface where any one of the constituent layers of the hard coating layer is exposed. ,
It is characterized by a coated cutting tip that exhibits excellent chipping resistance in a hard coating layer in high-speed cutting of high hardness steel.

The reason why the hard coating layer and the abrasive layer of the coated cutting chip of the present invention and the Al ₂ O ₃ fine particles of the polishing liquid used in wet blasting are limited numerically as described above will be described below.
(A) Hard coating layer (a-1) First adhesion bonding layer The TiN layer and the TiCN layer constituting the first adhesion bonding layer are either a chip base or a modified (Ti, Zr) CN layer which is a second layer. In addition, it has the effect of improving the tight bondability of the hard coating layer to the chip substrate, but if the average layer thickness is less than 0.1 μm, the desired excellent close bondability should be ensured. On the other hand, since the tight adhesion can be sufficiently secured with an average layer thickness of 1 μm, the average layer thickness was determined to be 0.1 to 1 μm.

(A-2) Modified high-temperature strengthened layer The distribution ratio of Σ3 in the constituent atomic shared lattice distribution graph of the modified (Ti, Zr) CN layer constituting the modified high-temperature strengthened layer that is the second layer of the hard coating layer is As described above, the content of TiCl ₄ and CH ₃ CN constituting the reaction gas, the content of CH ₄ , and the atmospheric reaction temperature can be adjusted to 60% or more. In this case, the distribution ratio of Σ3 is 60%. % Is less than 250 m / min. Since high-speed cutting at the above cutting speed does not cause chipping in the hard coating layer and an excellent effect of improving high-temperature strength cannot be ensured, the distribution ratio of Σ3 is set to 60% or more. As described above, the modified (Ti, Zr) CN layer has an even higher temperature strength in addition to the high temperature strength and heat resistance of (Ti, Zr) CN itself as described above. If the average layer thickness is less than 2.5 μm, the desired excellent high-temperature strength improvement effect cannot be sufficiently imparted to the hard coating layer, whereas if the average layer thickness exceeds 15 μm, the thermoplastic deformation causing uneven wear will occur. Therefore, the average layer thickness was determined to be 2.5 to 15 μm.
Further, as described above, the Zr component in the modified (Ti, Zr) CN layer has an effect of improving heat resistance and suppressing softening in a high-temperature atmosphere during cutting. If the value is an atomic ratio occupying the total amount with Ti, if less than 0.02, the desired heat resistance improvement effect cannot be obtained, while if the A value exceeds 0.15, the high temperature strength tends to decrease. Therefore, the A value indicating the content ratio of Zr was determined to be 0.02 to 0.15.
Furthermore, the C component in the modified (Ti, Zr) CN layer improves the hardness of the layer, while the N component has the effect of improving the strength. Therefore, if the content ratio (B value) of the N component in the layer is less than 0.3 in terms of the atomic ratio to the total amount with the C component, the desired strength should be ensured. On the other hand, if the content ratio (B value) similarly exceeds 0.55, the content ratio of the C component becomes relatively small and the desired high hardness cannot be obtained. The ratio was determined to be 0.3 to 0.55.

(A-3) Second adhesion bonding layer The TiCO layer and the TiCNO layer constituting the second adhesion bonding layer are a modified (Ti, Zr) CN layer as a _second layer and an Al ₂ O ₃ layer as a high-temperature hard layer. Both of them have a strong adhesive bond, and thus contribute to improving the tight bondability of the hard coating layer to the chip substrate. However, if the average layer thickness is less than 0.1 μm, the desired excellent close bondability is ensured. On the other hand, since the tight adhesion can be sufficiently secured with an average layer thickness of 1 μm, the average layer thickness was determined to be 0.1 to 1 μm.

(A-4) High-temperature hard layer The Al ₂ O ₃ layer constituting the high-temperature hard layer has excellent high-temperature hardness and heat resistance, and contributes to the improvement of the wear resistance of the hard coating layer. If the thickness is less than 1 μm, the hard coating layer cannot exhibit sufficient wear resistance. On the other hand, if the average layer thickness exceeds 15 μm, the chipping tends to occur. It was determined to be 1 to 15 μm.

(B) Abrasive material layer As described above, the titanium oxynitride layer constituting the upper layer first forms a titanium oxide layer in which the oxygen ratio is 1.25 to 1.90 (W value) in terms of atomic ratio to Ti. Then, it is formed by depositing a TiN layer on the titanium oxide layer under normal conditions. Therefore, diffusion of oxygen from the titanium oxide layer during the formation of the TiN layer is indispensable. When the W value of the titanium oxide layer is less than 1.25, the diffusion reaction of oxygen into the TiN layer is drastically reduced, and the ratio of diffused oxygen (Y value) in the upper layer is 0.01 by atomic ratio. On the other hand, if the same W value exceeds 1.90, the ratio of diffused oxygen (Y value) in the upper layer will increase beyond 0.40 in terms of atomic ratio. The value is defined as 1.25 to 1.90 In this case, the oxygen ratio (X value) in the lower layer (titanium oxide layer) after forming the upper layer takes a value in the range of 1.2 to 1.7 in terms of atomic ratio, in other words, the upper layer. When the X value of the lower layer after formation satisfies 1.2 to 1.7, the Y value of the upper layer satisfies 0.01 to 0.40.
In this case, the X value of the lower layer and the Y value of the upper layer are set to 1.2 to 1.7 and 0.01 to 0.40, respectively. It is obtained from many test results that these abrasive layers are pulverized and atomized in a suitable state at the time of wet blasting, and exhibit an excellent polishing function sufficiently. Based on this. Therefore, if the X value and Y value are out of the range of 1.2 to 1.7 and 0.01 to 0.40, respectively, the pulverization and atomization at the time of wet blasting of the abrasive layer is not satisfactorily performed, which is excellent. The polishing function cannot be expected.
Further, the average layer thicknesses of the upper layer and the lower layer were set to 0.05 to 2 μm and 0.1 to 3 μm, respectively, when the average layer thickness was less than 0.05 μm and less than 0.1 μm. The ratio of the pulverized titanium oxide fine particles in the lower layer and the fine pulverized titanium oxynitride fine particles in the upper layer is too small to perform the polishing function sufficiently, while the average layer thickness is 2 μm and 3 μm, respectively. Even if it exceeds the range, the polishing function will rapidly decrease, and in any case, the surface of the Al ₂ O ₃ layer cannot be polished to a surface roughness of Ra: 0.2 μm or less. It is.

(C) The Al ₂ O ₃ fine of Al ₂ O ₃ fine fraction polishing liquid of the polishing liquid, pulverization oxynitride of pulverized titanium oxide fine and the upper layer of the lower layer of the abrasive layer during wet blasting Although it acts to polish the surface of the Al ₂ O ₃ layer in the state of coexisting with the titanium fine particles, it is polished even if the ratio is less than 15% by mass or more than 60% by mass with respect to the total amount with water. Since the function suddenly decreases, the ratio is determined to be 15 to 60% by mass.

In the coated cutting tip of the present invention, the modified (Ti, Zr) CN layer constituting the second layer of the hard coating layer has the above-described high temperature strength and heat resistance provided by the (Ti, Zr) CN layer itself. Rake face part and flank face including at least cutting edge ridge line part of Al ₂ O ₃ layer which has higher high temperature strength than conventional (Ti, Zr) CN layer and further constitutes fourth layer of hard coating layer The hard coating layer in which the portion is polished to a surface roughness of Ra: 0.2 μm or less and is irradiated with a laser beam over one of the rake face and the flank face of the polished face, or the entire surface of both faces. The residual stress reduction pattern significantly improves the chipping resistance of the hard coating layer, and particularly when cutting hardened steel such as a hardened material of alloy tool steel or bearing steel, the cutting speed is 250 m / min. Even when used for the above high speed, chipping does not occur in the hard coating layer, it exhibits excellent cutting performance over a long period of time, and it is possible to further extend the service life. .

  Next, the coated cutting tip of the present invention will be specifically described with reference to examples.

WC powder, TiC powder, ZrC powder, VC powder, TaC powder, NbC powder, Cr ₃ C ₂ powder, TiN powder, TaN powder, and Co powder all having an average particle diameter of 1 to 3 μm are prepared as raw material powders. These raw material powders are blended into the composition shown in Table 1, added with wax, ball mill mixed in acetone for 30 hours, dried under reduced pressure, and then pressed into a green compact of a predetermined shape at a pressure of 98 MPa. The green compact was vacuum sintered at a predetermined temperature in the range of 1370 to 1470 ° C. for 1 hour in a vacuum of 5 Pa. After sintering, the cutting edge portion was R: 0.07 mm honing By processing, chip bases A to F made of a WC-based cemented carbide having a throwaway tip shape defined in ISO · SNMG120408 were manufactured.

In addition, as raw material powders, TiCN (mass ratio TiC / TiN = 50/50) powder, Mo ₂ C powder, ZrC powder, NbC powder, TaC powder, WC powder, all having an average particle diameter of 0.5 to 2 μm. Co powder and Ni powder were prepared, and these raw material powders were blended into the blending composition shown in Table 2, wet mixed by a ball mill for 30 hours, dried, and then pressed into a compact at a pressure of 98 MPa. The green compact was sintered in a nitrogen atmosphere of 1.3 kPa at a temperature of 1540 ° C. for 1 hour, and after the sintering, the cutting edge portion was subjected to a honing process of R: 0.07 mm. TiCN-based cermet chip bases a to f having a standard / SNMG12041 chip shape were formed.

(A) Next, a normal chemical vapor deposition apparatus is used on the surfaces of the chip bases A to F and the chip bases a to f, and first, a first layer composed of either a TiN layer or a TiCN layer, or a laminate of both. After the adhesion bonding layer is formed by vapor deposition with the target layer thickness shown in Table 7 under the conditions shown in Table 3, the modified (Ti, Zr) CN layer (modified high-temperature strengthened layer) is formed under the conditions shown in Table 4. The second adhesive bonding layer formed by vapor deposition with a target layer thickness shown in Table 7 and then a laminate of either or both of the TiCO layer and the TiCNO layer is shown in Table 7 under the conditions shown in Table 3. Vapor deposition with a target layer thickness, followed by vapor deposition with the target layer thickness shown in Table 7 under the same conditions as shown in Table 3, Al ₂ O ₃ layer (high temperature hard layer),
(B) Next, a lower layer forming titanium oxide layer [any one of TiO _W (1) to (6)] is formed on the entire surface of the Al ₂ O ₃ layer constituting the hard coating layer. Then, an upper layer forming titanium nitride layer (TiN layer) is vapor-deposited with the target layer thickness shown in Table 8 under the conditions shown in Table 5 and also shown in Table 8. The composition, that is, the central portion in the thickness direction is measured with an Auger spectroscopic analyzer, and an abrasive layer composed of a lower layer and an upper layer of the X value and Y value shown in Table 8 is formed (see FIG. 12).
(C) Subsequently, the coated cutting chip formed with the lower layer and the upper layer is subjected to wet blasting under the blasting conditions shown in Table 6 and in the combinations shown in Table 8, In the state where the abrasive layer is present around the mounting hole, the rake face portion and the flank face portion including the cutting edge ridge line portion of the Al ₂ O ₃ layer (high temperature hard layer) are also shown in Table 8 (See Fig. 13)
(D) Furthermore, using a laser beam irradiation device, the hard coating layer for surface polishing,
Laser beam output: 10W
The shape of a single basic shape mark: a circle with a diameter of 0.8 mm,
Hard coating layer residual stress reduction pattern: any one of the implementation patterns shown in FIGS.
Depth of digging on the exposed surface of a single basic shape mark: the depth shown in Table 8 as a percentage of the total target layer thickness of the hard coating layer,
The coated cutting chips 1 to 13 of the present invention were manufactured by forming a hard coating layer residual stress reduction pattern under the conditions described above.

(A) For comparison purposes, as shown in Table 9, the second hard coating layer was formed by vapor deposition under the conditions shown in Table 4 and with the target layer thickness shown in Table 9 (Ti , Zr) CN layer, the first and second adhesive bonding layers, and the Al ₂ O ₃ layer (high-temperature hard layer) are formed by vapor deposition under the same conditions as those of the coated cutting chips 1 to 13 of the present invention. (See FIG. 14),
(B) Subsequently, the Al ₂ O ₃ layer (high-temperature hard layer) was formed by performing wet blasting under the blasting conditions shown in Table 6 and the combinations shown in Table 9 without forming the abrasive layer. The conventional coated cutting chips 1 to 13 were manufactured by polishing the rake face and the flank face including the cutting edge ridge line portion of (1) to the surface roughness similarly shown in Table 9.

Next, a modified (Ti, Zr) CN layer and a conventional (Ti, Zr) CN layer constituting the hard coating layer of the present invention-coated cutting tip and the conventional coated cutting tip are used by using a field emission scanning electron microscope. Each component atom shared lattice distribution graph was created.
That is, the constituent atomic shared lattice point distribution graph shows a mirror of a field emission scanning electron microscope in a state where the surfaces of the modified (Ti, Zr) CN layer and the conventional (Ti, Zr) CN layer are polished surfaces. An electron beam with an acceleration voltage of 15 kV at an incident angle of 70 degrees is applied to the polished surface with an irradiation current of 1 nA to each crystal grain existing within the measurement range of the surface polished surface. Using a backscatter diffraction image apparatus, a (001) plane and a (011) plane that are crystal planes of the crystal grains with respect to the normal line of the surface-polished surface in a 30 × 50 μm region at an interval of 0.1 μm / step The inclination angle formed by the normal of the surface is measured, and based on the measurement inclination angle obtained as a result, each of the constituent atoms is one constituent atom between the crystal grains at the interface between adjacent crystal grains. Shared lattice points (constituent atom shared lattice points The constituent atomic shared lattice in which there are N lattice points that do not share constituent atoms between the constituent atomic shared lattice points (N is an even number of 2 or more in the crystal structure of the NaCl type face centered cubic crystal) When the point form is expressed as ΣN + 1, it is created by calculating the distribution ratio of each ΣN + 1 to the entire ΣN + 1 (however, the upper limit value is 28 due to the frequency).

  As a result, in the constituent atomic shared lattice distribution graph of various modified (Ti, Zr) CN layers and conventional (Ti, Zr) CN obtained as a result, the entire ΣN + 1 (N is an even number in the range of 2 to 28) Tables 7 and 9 show the distribution ratio of Σ3 in the table.

In the above-mentioned various constituent atomic share lattice point distribution graphs, as shown in Tables 7 and 9, respectively, the modified (Ti, Zr) CN layer of the coated cutting tip of the present invention has a distribution ratio of Σ3 of 60%. In contrast to the constituent atom shared lattice point distribution graph described above, the conventional (Ti, Zr) CN layer of the conventional coated cutting tip has a Σ3 distribution ratio of 30% or less in the constituent atomic shared lattice point distribution graph. Was shown.
FIG. 3 is a graph showing the distribution of constituent atomic shared lattice points of the modified (Ti, Zr) CN layer of the coated cutting tip 1 of the present invention, and FIG. 4 is a graph of the conventional (Ti, Zr) CN layer of the conventional coated cutting tip 1. The constituent atom shared lattice point distribution graphs are respectively shown.

  Further, for the above-described coated cutting chips 1 to 13 of the present invention and the conventional coated cutting chips 1 to 13, the constituent layers of the hard coating layer were observed using an electron beam microanalyzer (EPMA) and an Auger spectroscopic analysis device (layer When the longitudinal section was observed), it was confirmed that both the former and the latter had substantially the same composition as the target composition. Moreover, when the thickness of the constituent layer of the hard coating layer of these coated cutting tips was measured using a scanning electron microscope (same longitudinal section measurement), the average layer thickness (which is substantially the same as the target layer thickness) Average value of 5-point measurement) was shown.

Next, for the various coated cutting chips of the present invention coated cutting chips 1 to 13 and the conventional coated cutting chips 1 to 13 described above, all of them are screwed to the tip of the tool steel tool with a fixing jig,
Workpiece: hardened material of JIS · SKD11 (hardness _H R C: 55) round bar,
Cutting speed: 280 m / min,
Cutting depth: 0.7mm,
Feed: 0.12 mm / rev,
Wet continuous high-speed cutting test (normal cutting speed is 130 m / min) of alloy tool steel under the following conditions (referred to as cutting condition A),
Workpiece: hardened material of JIS · SUJ2 (hardness _H R C: 56) round bar,
Cutting speed: 260 m / min,
Cutting depth: 0.4mm,
Feed: 0.13mm / rev,
Wet continuous high-speed cutting test (normal cutting speed is 120 m / min) of bearing steel under the conditions (referred to as cutting condition B),
Workpiece: hardened material of JIS · SKD61 (hardness _H R C: 54) round bar,
Cutting speed: 270 m / min,
Cutting depth: 0.55 mm,
Feed: 0.12 mm / rev,
Wet continuous high-speed cutting test (normal cutting speed is 140 m / min) of alloy tool steel under the above conditions (referred to as cutting condition C), and the flank wear width of the cutting edge is generally determined by the cutting tool. The cutting time until reaching 0.3 mm, which is regarded as a standard for the service life, was measured. The measurement results are shown in Table 10.

From the results shown in Tables 7 to 10, all of the coated cutting tips 1 to 13 of the present invention are modified to show the constituent atomic shared lattice point distribution graph in which the second hard coating layer has a Σ3 distribution ratio of 60% or more. The modified (Ti, Zr) CN layer has a high temperature strength which is superior to that of the modified (Ti, Zr) CN layer, and at least an Al ₂ O ₃ layer constituting the fourth layer of the hard coating layer. The rake face portion and the flank face portion including the cutting edge ridge line portion are polished to a surface roughness of Ra: 0.2 μm or less, and the hard coating layer residual stress is reduced by laser beam irradiation over the entire polished surface. Combined with the fact that the residual tensile stress in the hard coating layer is remarkably reduced depending on the pattern, even when various high hardness steels are cut at a high cutting speed of 250 m / min or more, chipping is performed on the hard coating layer. Without the occurrence of Conventional (Ti, Zr) CN in which the second layer of the hard coating layer exhibits a constituent atomic shared lattice point distribution graph in which the distribution ratio of Σ3 is 30% or less, while exhibiting excellent cutting performance over the period The surface roughness of the Al ₂ O ₃ layer that is composed of the layers and constitutes the fourth layer of the hard coating layer is Ra: 0.3 to 0.6 μm, and the hard coating layer residual stress reduction pattern is formed. None of the conventional coated cutting tips 1 to 13 may cause chipping in the hard coating layer in the cutting of high-hardness steel at a high speed of 250 m / min or more, leading to a service life in a relatively short time. it is obvious.

  As described above, the coated cutting tip of the present invention is not only used for high-speed cutting of various general steels and ordinary cast iron, but particularly when high-hardness steel is cut at a high cutting speed of 250 m / min or higher. Excellent chipping resistance and excellent cutting performance over a long period of time, fully satisfying high performance of cutting equipment, labor saving and energy saving of cutting, and cost reduction It can respond.

It is a schematic diagram which shows the crystal structure of the NaCl type face centered cubic crystal which the (Ti, Zr) CN layer which comprises the 2nd layer of a hard coating layer has. It is a schematic explanatory drawing which shows the measurement aspect of the inclination angle of the (001) plane of a crystal grain and the (011) plane in the (Ti, Zr) CN layer which comprises the 2nd layer of a hard coating layer. 4 is a constituent atomic shared lattice point distribution graph of a modified (Ti, Zr) CN layer constituting the second layer of the hard coating layer of the present coated cutting tip 1. 4 is a constituent atomic shared lattice point distribution graph of a conventional (Ti, Zr) CN layer constituting a lower layer of a hard coating layer of a conventional coated cutting tip 1. It is a schematic perspective view of this invention coating cutting tip which formed the hard coating layer residual stress reduction pattern as an Example by laser beam irradiation formation. FIG. 6 is a schematic perspective view of a coated cutting tip of the present invention in which a hard coating layer residual stress reducing pattern as an embodiment other than FIG. 5 is formed by laser beam irradiation. FIG. 7 is a schematic perspective view of a coated cutting tip of the present invention in which a hard coating layer residual stress reduction pattern as an embodiment other than FIGS. FIG. 8 is a schematic perspective view of a coated cutting tip of the present invention in which a hard coating layer residual stress reduction pattern as an embodiment other than FIGS. FIG. 9 is a schematic perspective view of a coated cutting tip of the present invention in which a hard coating layer residual stress reducing pattern as an embodiment other than FIGS. FIG. 10 is a schematic perspective view of a coated cutting tip of the present invention in which a hard coating layer residual stress reduction pattern as an embodiment other than FIGS. FIG. 11 is a schematic perspective view of a coated cutting tip of the present invention in which a hard coating layer residual stress reducing pattern as an embodiment other than FIGS. It is a schematic perspective view which shows the state which formed the abrasive material layer in the whole surface of the hard coating layer. It is a schematic perspective view which shows the state after giving wet blast in the state which formed the abrasive material layer. It is a schematic perspective view of the conventional coated cutting tip.

Claims (1)

On the entire rake face and flank face including the cutting edge ridge line portion of the cermet base composed of tungsten carbide base cemented carbide or titanium carbonitride base cermet,
(1) As the first layer, a first adhesion formed of either a titanium nitride layer or a titanium carbonitride layer formed by chemical vapor deposition, or a laminate of both layers, and having an average layer thickness of 0.1 to 1 μm. Bonding layer,
(2) The second layer is formed by chemical vapor deposition,
Composition formula: (Ti _1-A Zr _A ) C _1-B N _B (wherein A is 0.02 to 0.15 and B is 0.3 to 0.55 in atomic ratio),
A high-temperature strengthened layer comprising a composite carbonitride layer of Ti and Zr that satisfies the following conditions and having an average layer thickness of 2.5 to 15 μm;
(3) As the third layer, the first layer is composed of either a titanium carbonate layer formed by chemical vapor deposition or a titanium carbonitride oxide layer, or a laminate of both layers, and has an average layer thickness of 0.1 to 1 μm. 2 adhesive bonding layers,
(4) As the fourth layer, a high-temperature hard layer comprising an aluminum oxide layer formed by chemical vapor deposition and having an average layer thickness of 1 to 15 μm,
In the surface-coated cermet cutting tool formed by forming the hard coating layer constituted by the above (1) to (4),
( _A ) _A high-temperature strengthening layer, which is the second layer of the hard coating layer, is also formed by chemical vapor deposition, and has a composition formula (Ti _1-A Zr _A ) C _1-B N _B (however, in terms of atomic ratio, A Is 0.02 to 0.15, B is 0.3 to 0.55), and further has an average layer thickness of 2.5 to 15 μm.
Using a field emission scanning electron microscope, each crystal grain existing within the measurement range of the surface polished surface is irradiated with an electron beam, and the crystal plane of the crystal grain is normal to the surface polished surface ( The inclination angle formed by the normal lines of the (001) plane and the (011) plane is measured. In this case, the crystal grains are NaCl-type face-centered cubes each having a constituent atom composed of Ti, Zr, carbon, and nitrogen at lattice points. A lattice in which each of the constituent atoms shares one constituent atom between the crystal grains at the interface between adjacent crystal grains based on the measured tilt angle obtained as a result of the crystal structure The distribution of the points (constituent atom shared lattice points) is calculated, and there are N lattice points that do not share the constituent atoms between the constituent atom shared lattice points (N is an even number of 2 or more in the crystal structure of the NaCl type face centered cubic crystal). ΣN is the existing configuration of atomic atom lattice points. In the constituent atom sharing lattice distribution graph showing the distribution ratio of each ΣN + 1 in the entire ΣN + 1 (however, the upper limit value is 28 due to the frequency), the highest peak exists in Σ3, A modified high-temperature strengthened layer composed of a composite carbonitride layer of Ti and Zr showing a constituent atom shared lattice point distribution graph in which the distribution ratio of Σ3 in the entire ΣN + 1 is 60% or more,
Consisting of
(B) on the entire surface of the aluminum oxide layer which is the fourth layer of the hard coating layer,
(B-1) The lower layer has an average layer thickness of 0.1 to 3 μm, and
Composition formula: TiO _x ,
, The central part in the thickness direction is measured with an Auger spectrometer, and the atomic ratio is
X: 1.2 to 1.7,
Satisfying titanium oxide layer,
(B-2) The upper layer has an average layer thickness of 0.05 to 2 μm, and
Composition formula: TiN _1-Y (O) _Y ,
(Where (O) indicates diffused oxygen from the titanium oxide layer), the central portion in the thickness direction is also measured with an Auger spectroscopic analyzer, and the atomic ratio is
Y: 0.01 to 0.4
Satisfying titanium oxynitride layer,
In a state where the abrasive layer constituted by (b-1) and (b-2) is formed by vapor deposition,
(B-3) In wet blasting, as a spraying abrasive, a polishing liquid containing 15 to 60% by mass of aluminum oxide fine particles in a proportion of the total amount with water is sprayed,
The aluminum oxide layer constituting the fourth layer of the hard coating layer in the presence of the pulverized titanium oxide fine particles in the lower layer, the pulverized titanium oxynitride fine particles in the upper layer, and the aluminum oxide fine particles as the spray abrasive The rake face portion and the flank face portion including at least the cutting edge ridge line portion are polished, and the surface roughness of these polished surfaces is measured on the basis of compliant standard JIS B0601-1994, Ra: 0.2 μm or less,
(C) Further, any one of the rake face and the flank face of the polished surface of the aluminum oxide layer, or any one of the single basic shape mark and the collective mark of the single basic shape mark, Both are distributed and distributed, and the hard basic layer residual stress reduction pattern is formed by laser beam irradiation with the single basic shape mark as a dug surface with any of the constituent layers of the hard coating layer exposed. What
A surface-coated cermet cutting throwaway tip that exhibits excellent chipping resistance in high-speed cutting of high-hardness steel with a hard coating layer.

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